|Cooper, Rodney - William|
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/2015
Publication Date: 6/14/2015
Publication URL: http://handle.nal.usda.gov/10113/60986
Citation: Cooper, W.R., Spurgeon, D.W. 2015. Temperature-dependent survival of adult Lygus hesperus (Hemiptera: Miridae). Environmental Entomology. 44:808-813.
Interpretive Summary: The western tarnished plant bug, Lygus hesperus, is a key pest of fruit, vegetables, and cotton in the western United States, but many aspects of its overwintering biology are poorly understood. Researchers at the USDA-ARS in Shafter, CA examined the influence of temperature on survival of western tarnished plant bug adults held with or without food, and the effects of an extended exposure at 50 degrees F on subsequent reproduction. They showed that females lived longer than males and survival time decreased as temperatures increased from 50 to 90 degrees F. They also showed that unfed insects can live for more than 190 days when held at 50 degrees F, and insects held for extended periods without food were as likely to mate, and produced as many eggs, as insects held with food. These results suggest that adults can survive the winter even if feeding hosts are available only intermittently. This study provides models of the temperature-dependent survival of western tarnished plant bug adults, and information critical to better understanding overwintering ecology of this pest. This information will be useful to researchers investigating seasonal plant bug population dynamics, and will help in development of new control strategies which target overwintering plant bug populations.
Technical Abstract: The western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae), is a key pest of many horticultural and agronomic crops in the western United States. Despite its well documented pest status, many aspects of the basic biology, including overwintering ecology, of L. hesperus are poorly understood. We examined the influence of eight constant temperatures from 10 to 35 degrees C on survival of non-diapausing adult L. hesperus held with or without food, and the consequences of exposure to an extended period at 10 degrees C on subsequent reproduction. Survival analyses indicated that on average, fed insects tended to live longer than unfed insects, females lived longer than males, and survival time decreased with increasing temperature. Non-linear regressions indicated median survival for insects grouped by gender and feeding status declined exponentially with increasing temperature. Survival functions for combinations of insect class (gender, feeding status) and temperature were adequately described by respective two-parameter logistic functions. When adults were held for 9 d at 27 degrees C with food following a 33-d period at 10 degrees C either with or without food, no deleterious effects of prior starvation on propensity to mate or fecundity were demonstrated. These findings indicate that when temperatures are low, non-diapausing L. hesperus adults are capable of extended host-free survival with little or no impact on subsequent reproduction. Our findings suggest the current understanding of L. hesperus overwintering dynamics is incomplete. In addition, our results provide quantitative baseline information to facilitate more comprehensive investigation of the ecology of L. hesperus overwintering.